That indeed is not the true essence we see in Andy. He's far more emotional and genuine. But anyway, sometimes Andy makes mistakes too and perhaps he was talked into it. He's not that type the one on the cover.
Most people have little to no input concerning what graphics are on the cover of their books. Those decisions are made at the discretion of the publishers, unless you're super successful and are granted input on such things. I'd bet anything Andy had no idea what was going to be on the front of his book until they showed it to him.